Scripted boss fights are entirely possible, they are not all that resource-intensive (although precise timing is difficult), and forcing certain music to play throughout a dungeon or boss encounter is also possible. It should also be possible to script camera-work like in the video you posted, although I haven't made an attempts to actually try that.
Right now I have one scripted encounter that takes place in a large, open space, and a second one that takes place in a cramped arena, that only closes up on you after you step into an apparently open area. Each has a script introduction sequence that essentially forces the player to take certain actions to reveal the boss. For the Fire Guardian, there is a large, smokey area which you search, while hearing the sound of a large animal always just out of sight. When you leave the area, it shows up behind you, growling, but doesn't begin attacking until you turn around and look at it. It's... pretty scary, and there's no force camera work involved

For the Frost Guardian, you approach an apparently open area, only to have it quickly fill with fog. When it clears, the walls of ice surround you completely and the Guardian itself is standing on stop of one of them, looking down at you, back-lit by blue/violet auroras, before flying down to start beating on you.
As for scripting the fight itself, the results can be... impressive. Here is some of my WIP for my elemental Guardians.
The Fire Guardian battle is fast and furious. It takes place in a huge, open area, and relies on breaking him down and taking out the pieces one by one to weaken the boss himself. This video is missing a lot of the animations and transitions I've added since:
https://www.youtube.com/watch?v=sNmTlDhpc_4
The Frost Guardian battle is claustrophobic. Although he moves slowly, he does many things to impede your movement as well as draining your stamina. This in combination with cramped surroundings and his penchant for always being much closer to you than you think he is make for a continual state of near-panic during the fight (headphone users beware, I accidentally captured the wrong audio track with this one and it's LOUD):
https://www.youtube.com/watch?v=GAzNaxiRs5Q
Obviously these need a lot more polishing, but you can see where I'm going. I want boss fights the player will actually remember, instead of yet another generic dragon priest or draugr lord.